1. Field of the Invention
The present invention relates to a ground drilling machine such as earth drilling (boring) machine for drilling a bore in earth for embedding, without open-cut operation to the earth, gas pipe, electric cable, signal cable sheath tube, fiber cable, water-supply pipe, sewer (sewage) pipe and the like, and a crawler drill for boring an earth to insert an explosive for blasting use, and also relates to a rod exchanger utilized for such ground drilling machine.
2. Prior Art
Prior art provides a crawler drill such as disclosed in Japanese Patent Laid-open Publication No. SHO 58-189493.
The crawler drill disclosed in this publication is equipped with a freely travelling vehicle body, a frame structure mounted to the vehicle body, a drilling unit movable along the frame structure, a rod having, at its front end, a drill bit and rotated and propelled by this drilling unit and a rod exchanger mounted to the frame structure. The rods are incorporated in the rod exchanger so that the rods are accommodated in turns to the drilling unit to sequentially drill the earth (ground).
This rod exchanger is provided with a main body into which a plurality of rods are accommodated and a rod exchanging unit or section mounted to the main body so as to carry the rods between the main body and the frame structure. The main body of the rod exchanger is mounted to the side surface of the frame structure.
Accordingly, in such crawler drill of the prior art, since the rod exchanger is cantilevered by the frame structure, a large load is applied to the frame structure, so that it is obliged to make the frame structure large and heavy.
Furthermore, in such crawler drill, a large bending load will be applied to the machine body of the rod exchanger, and particularly, a large load will be applied to a portion of the machine body which is mounted to the frame structure. Therefore, it becomes necessary to make the strength of that portion large so as to allow an entire weight of the rod exchanger to be supported, thus making the size and weight of the rod exchanger large and heavy, being disadvantageous.
As mentioned above, large size and heavy weight of the frame structure and the rod exchanger result in large load acting on the vehicle body of the crawler drill, and hence, the vehicle body itself is made large and heavy.
Such defects bring the entire structure of the crawler drill having a large size and heavy weight, and hence, it is difficult to carry out the drilling working by the crawler drill set at a narrow site or portion. The entire height (from the ground surface) of the crawler drill is high, preventing worker""s visibility, and moreover, it is difficult for the worker to exchange the rods and carry out the rod propelling operation and, moreover, any safe operation cannot be expected because of high position of the gravity center of the crawler drill.
The body of the rod exchanger is formed with a plurality of rod accommodation (receiving) recesses arranged along a circular locus thereof. The rod exchanging unit is composed of a swingable arm and a pair of claws provided, to be opened or closed, at the front end portion of the arm. A rod accommodated in the recess formed to the rod exchanger body is grasped by the paired claws, and the arm is swung and carried to the frame. When reached to the frame, the rod is released from the claws and the rod is then connected to the drilling unit. According to the manner reverse to that mentioned above, the rod is accommodated in the recess of the rod exchanger body.
In order to carry out the aforementioned operation, it is necessary to secure a large space for the swing motion of the claws in opposite sides of the rod diametral direction at the time when the rod received in the rod accommodation recess is grasped. Therefore, the fact that the large space is required leads to a defect that it is necessary to increase a distance between adjacent two rods accommodated in the recesses of the rod exchanger body, and hence, the number of the rods to be accommodated is reduced.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a ground drilling machine capable of making a frame structure light and compact and a rod exchanger utilized therefor capable of accommodating a lot of rods without increasing an arrangement or location space.
This and other objects can be achieved according to the present invention by providing a ground drilling machine comprising:
a machine body;
a rod propelling device having a frame structure mounted to the machine body;
a rod exchanging device mounted to the frame structure of the rod propelling device; and
a support unit provided for the machine body for supporting the rod exchanging device.
According to this structure, since the rod exchanging device is supported by the machine body, a load to be applied to the frame structure of the rod propelling device can be reduced, so that the frame structure can be made light and compact.
Furthermore, since a large bending load is not applied to the main body portion of the rod exchanging device, the rod exchanging device itself can be made light and compact. Particularly, any large load is not applied to the portion through which the rod exchanging device is mounted to the frame structure, so that this portion can be especially made light and compact.
As mentioned above, the frame structure, the rod exchanging device and the portion through which the rod exchanging device is mounted to the frame structure are all made light and compact, so that the load to be applied to the machine body can be reduced, thus making the machine body compact and light, resulting in the realization of the light and compact entire structure of the ground drilling machine.
Accordingly, the ground drilling machine having a large working capacity can be installed in a narrow working site such as on a sidewalk or a narrow path, thus improving a working efficiency.
Moreover, since the total height of the ground drilling machine can be made low, the visibility of an operator can be improved and the rod exchanging working and rod propelling working can be performed smoothly. Also, the ground drilling machine can have a low center of gravity to be stable.
In a preferred embodiment of the above aspect, the frame structure is movably mounted to the machine body and also the rod exchanging device is movably supported by the support unit also.
According to this structure, the rod exchanging device is moved together with the frame structure, so that the rod propelling device can be easily set to an aimed ground position. Moreover, since the positional relationship between the frame structure and the rod exchanging device is always constant, the rod exchanging working can be done regardless of the position of the frame structure.
Furthermore, the frame structure and the rod exchanging device can be simultaneously moved with respect to the machine body and the support portion of the machine body, respectively, the width of the moving contact portions thereof can be made large, so that the movement thereof can be stably performed and the machine body can be easily and accurately set to the aimed position with less swing motion thereof.
Furthermore, according to the present invention, there is also provided a rod exchanging device, particularly for the ground drilling machine of the aspect mentioned above, comprising:
a main body portion;
a rod accommodation portion mounted to the main body portion for accommodating a plurality of rods with a space from each other; and
a rod exchanging unit provided with a rod grasping device having a grasping portion which is movable between a position inside the main body portion and a position outside the main body portion, the grasping portion being formed with a fixed portion and a movable portion.
According to this structure, the rod can be grasped by both the fixed portion and the movable portion even in a presence of a small space capable of one movable portion being moved near the rod accommodated in the rod accommodation portion, and therefore, the space between the adjacent rods accommodated in the rod accommodation portion can be made small and, hence, a lot of rods can be accommodated.
The rod accommodation portion may provide a disc shaped structure adapted to accommodate a plurality of rods along the circular locus thereof with a space from each other and to be rotatable.
According to this structure, rod accommodation portion can be made rotatable which requires less space for accommodation, thus providing a light and compact rod exchanging device.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.